EP0408697A1 - Gerät zum punktweisen ausmessen von farbigen kopiervorlagen. - Google Patents
Gerät zum punktweisen ausmessen von farbigen kopiervorlagen.Info
- Publication number
- EP0408697A1 EP0408697A1 EP90900854A EP90900854A EP0408697A1 EP 0408697 A1 EP0408697 A1 EP 0408697A1 EP 90900854 A EP90900854 A EP 90900854A EP 90900854 A EP90900854 A EP 90900854A EP 0408697 A1 EP0408697 A1 EP 0408697A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- measuring
- original
- point
- light
- template
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B27/00—Photographic printing apparatus
- G03B27/72—Controlling or varying light intensity, spectral composition, or exposure time in photographic printing apparatus
- G03B27/73—Controlling exposure by variation of spectral composition, e.g. multicolor printers
- G03B27/735—Controlling exposure by variation of spectral composition, e.g. multicolor printers in dependence upon automatic analysis of the original
Definitions
- the invention relates generally to the field of color exposure of photographic substrates in the production of prints from a film original.
- the invention relates to a measuring device for point-by-point measurement of photographic master copies for the purpose of determining the exposure values when copying the original by means of a photographic enlarger or copier.
- the method used is based on the so-called principle of integration to gray, which assumes that the colors of an image integrate into neutral gray over the entire image area, because the recording scene typically has the same proportions of all three basic colors, red , Contains green and blue. On the basis of this principle, a constant color balance is maintained in the prints if the exposure is aimed at maintaining a constant ratio of the primary color components in the copying light.
- the measurement of a template to be copied is restricted thus relates to a color-selective measurement of the integral transmission density in the colors red, green and blue and a comparison thereof with that of a reference template for which the exposure values have already been determined in order to make corrections to the exposure values as a function of any deviation ⁇ men.
- the procedure practically boils down to producing the same color balance for a number of originals to be copied, which the reference originals have.
- the integral measuring method has the advantage of simplicity because the measuring device that is necessary for this is relatively simple and the implementation of the measurement, in particular the positioning of the measuring probe, is not critical.
- the integral evaluation based on the mean color density of the original proves to be inadequate in the event that the image to be reproduced has a strong color dominant.
- the criterion of always restoring the color balance of the reference original in deduction actually leads to a falsification of the color of the copy compared to the original.
- the integral measurement thus leads, at least in part of the copies, to an unsatisfactory color rendering, the repetition of the exposure with correspondingly correct exposure values required. The goal of obtaining the highest possible yield of satisfactory first copies by measuring the originals is accordingly not achieved.
- a photometric rotation sensor for translucent originals which allows the original to be scanned point by point.
- a rotary cylinder which performs a rotary movement and a linear movement at the same time, several light sensors are attached, to which the measuring light is supplied via light guide rods that reach as far as the image template.
- the electrical signals from the sensors are picked up via slip rings on the rotary cylinder and electronically
- each signal reaching the memory can be assigned to a fixed measuring point on the template via corresponding coding elements.
- the point-by-point measurement of the entire image area enables a more precise detection of the color distribution in the original than the integral measurement and, when using suitable criteria for signal evaluation, leads to an increased yield of satisfactory first copies.
- the sensor device described with the combined rotary and linear movement and the tapping of the sensor signals from a rotating sensor carrier proves to be relatively complex and cumbersome, in particular in the case of larger-sized originals, if the entry surfaces of the light guide rods move in an x- ⁇ movement the image area to be moved.
- video analyzers which are equipped with their own measuring light source and provide a positive control image on a screen from a template. They enable a direct assessment of the visualized image and the setting the image color by suitable signal influencing.
- a basic calibration with respect to a reference template is carried out again in order to obtain information about the densitometric differences of the template to be copied from the reference template and to calculate the settings to be made on the enlarger or copier in a downstream computing device .
- good results can generally be achieved with regard to the yield of satisfactory first copies.
- the complexity of the system and the associated high cost considerably restrict its area of application.
- the invention has for its object to provide an analyzer for film originals that provides a high yield of satisfactory first copies and requires less technical effort and correspondingly lower production costs compared to the known devices.
- This object is achieved according to the invention in a device of the type specified with an illumination device for illuminating the original, a photoelectric sensor device for color-selective detection of the measuring light shining through the template and a signal evaluation device connected downstream of the sensor device Combination of the following features solved:
- the illuminating device has a measuring light source, a light condenser and a step lens (Fresnel lens) in the vicinity of the original; -
- the template is imaged via a lens in the measuring plane of the sensor device, color filters in the colors red, green and blue being selectively insertable into the beam path near the lens and
- the sensor device has a photodiode line, which can be moved in a straight line in the imaging plane of the objective over the original image.
- a condenser light source and the additional arrangement of a step lens near the film template result in a high light concentration in the area of the template, so that a lamp of limited power suffices to illuminate the template with such a luminous intensity that the transmission light can be measured without problems . Thanks to the limited power of the lamp, special cooling devices are not necessary.
- the combination of a condenser light source and a stepped lens enables uniform illumination of the original with a short light path between the light source and the original, in favor of a simple and compact design of the lighting device and the device itself.
- the directional light guidance also proves to be advantageous with regard to the handling of the device because the ambient light in the open area between the image stage and the measuring head does not influence the measurement, so that the device can be used in the bright room despite free access to the image stage.
- the directional condenser light produces little glare.
- the photodiodes are preferably mounted as individual diodes in a cell shape together with components of a downstream amplifier and switching circuit on a printed circuit board which can be moved in a straight line in one plane.
- the circuit board is preferably driven by a step motor, such that the photodiode line sweeps over the projected original image in a number of successive steps and the measurement signals which arise can be clearly assigned to a respective measurement point.
- Figure 1 is a schematic representation of the measuring device according to the invention.
- FIG. 2 is an illustration of the drive for linear movement of a photoelectric sensor device of the device according to FIG. 1.
- the device according to the invention comprises a closed lower housing part 1 which receives an illumination device and an upper part 2 with a device for measuring light. Both parts are connected to one another with an eccentric carrier 3, the arrangement being such that the upper part is held as a light measuring head at a distance from the lower housing part.
- the lower housing part On the side facing the measuring head, the lower housing part has a working surface 4, in which an image stage 5 for receiving a film template 6 to be measured and further operating elements are arranged.
- the image stage is preferably removable, so that image stages for different film formats can be used interchangeably.
- the lower housing part and the measuring head together form a structural unit, with a freely accessible working area between the two in the area of the image stage holder.
- the lighting device in the interior of the lower housing part 1 comprises a light source 7, a condenser 8 and an additional step lens (Fresnel lens) 9 in the vicinity of the image stage, all in such an arrangement that the film template in the image stage is the same ⁇ mig is illuminated.
- a lens 10 is arranged in alignment with the central normal of the image stage, which sharply depicts the original located in the image stage in an image plane 14.
- a filter disk 11 has color filters 13, 13 ⁇ and 13 ′′ arranged along a circular line in the colors red, green and blue (of which only the filters 13 and 13 'are visible in the drawing) and is one Fixed axis 12 can be rotated in the center of the circular line, so that the color filters can be introduced one after the other into the measuring light beam path in the vicinity of the objective.
- the representation of the template via an optical system with the arrangement of the measuring filter near the lens is also advantageous in that one doing with small-area color filters.
- a cell-shaped photoelectric sensor arrangement preferably a photo diode row 15, extends in the image plane 14 over the narrow side of the image and can be moved linearly in the direction of the long side, so that it sweeps over the entire image of the original.
- the reference numeral 16 generally designates a motor drive for the linear movement of the photodiode array and the reference numeral 17 denotes an electronic signal evaluation circuit for evaluating and further processing the light measurement signals emitted by the photodiodes.
- FIG. 2 shows the drive and movement mechanism of the photodiode array 15 when scanning the measuring surface in isolation and on a larger scale than in FIG. 1.
- a number of photodiodes are mounted in a cell shape on a printed circuit board 18, which also accommodates at least some of the electronic components of a downstream amplifier and switching circuit (not shown in the figure).
- the printed circuit board 18 is connected to two by means of screw connections 19 Fixed sliding jaws 20 and 21, which are slidably displaceable on parallel guides 22, 23.
- the guides 22, 23 are held at the ends in a frame 24, the arrangement of the guides within the frame and the arrangement of the frame itself inside of the measuring head is such that the circuit board 18 can be moved normally in a plane parallel to the image plane 14 for the alignment of the photodiode array 14.
- a stepping motor 27 is provided, on the shaft of which a toothed disk 26 A toothed belt 25 runs over the toothed pulley 26 and a deflection roller 28 and extends in the area d he printed circuit board, to which it is firmly connected by means of a clamping connection 29, parallel to the guides 22, 23.
- the photodiode array can be moved step by step over the image area, as a result of which the film original is scanned over the entire area.
- the diode line is first moved from a fixed starting position outside the measuring field to the format-dependent measuring surface in order to recognize the format of the present film template from the distance until the illuminated measuring surface is reached.
- the template is scanned three times with the diode line, the red, green or blue color filter of the filter disk 11 (FIG. 1) being screwed into the measuring beam path.
- the measured values supplied one after the other by the individual photodiodes are stored in a memory device of the signal evaluation circuit and, in accordance with a predetermined algorithm, arithmetically converted into exposure values.
- the number of measurable measuring points of a template is, for example, 100 to 130 depending on the template format.
- the large number of light measurement values reflects the actual color distribution in the original to be copied and thus enables an image-specific calculation of the exposure values.
- the calculation is carried out with the aid of a microprocessor system, which also takes on the necessary control functions, including the motor control for driving the photodiode array.
- the calculated exposure values are digitally displayed on a display device.
- the device according to the invention also interfaces for data output via data printer, barcode printer or in online mode in connection with fully automatic enlarging devices. Designed as an independent device, it can be used as a color analyzer in the darkroom as well as a central measuring station in the photo laboratory.
Landscapes
- Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- General Physics & Mathematics (AREA)
- Spectrometry And Color Measurement (AREA)
- Control Of Exposure In Printing And Copying (AREA)
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT672488 | 1988-12-29 | ||
IT8806724U IT218047Z2 (it) | 1988-12-29 | 1988-12-29 | Dispositivo analizzatore di originali fotografici nella stampa fotografica |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0408697A1 true EP0408697A1 (de) | 1991-01-23 |
EP0408697B1 EP0408697B1 (de) | 1993-10-27 |
Family
ID=11121863
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP90900854A Expired - Lifetime EP0408697B1 (de) | 1988-12-29 | 1989-12-18 | Gerät zum punktweisen ausmessen von farbigen kopiervorlagen |
Country Status (6)
Country | Link |
---|---|
US (1) | US5128710A (de) |
EP (1) | EP0408697B1 (de) |
JP (1) | JPH03503092A (de) |
DE (1) | DE58906045D1 (de) |
IT (1) | IT218047Z2 (de) |
WO (1) | WO1990007728A1 (de) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5303000A (en) * | 1991-06-07 | 1994-04-12 | Agfa-Gevaert Aktiengesellschaft | Method of and apparatus for ascertaining the characteristics of shorter and longer sections of photographic material |
JPH0822081A (ja) * | 1994-07-08 | 1996-01-23 | Fuji Photo Film Co Ltd | 写真プリンタ及びフイルムスキャナー |
DE19539690C2 (de) * | 1995-10-25 | 1998-09-10 | Agfa Gevaert Ag | Kopiergerät |
EP1213569B1 (de) * | 2000-12-08 | 2006-05-17 | Gretag-Macbeth AG | Vorrichtung zur bildelementweisen Ausmessung eines flächigen Messobjekts |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2439308A1 (de) * | 1974-08-16 | 1976-02-26 | Hoechst Ag | Verfahren und vorrichtung zur steuerung der belichtungszeit in mikrofilmrueckvergroesserungsgeraeten |
FR2515370A1 (en) * | 1981-10-23 | 1983-04-29 | Priox Sa | Photographic negative density analysing machine - includes photodetectors receiving light through specified points determined by passing perforated template, of negative for store in memory |
DE3512744A1 (de) * | 1985-04-09 | 1986-10-16 | Brodhag, geb. Lebe, Helga, 8999 Scheidegg | Fotometrischer rotationssensor fuer durchscheinende vorlagen |
DD259327A3 (de) * | 1986-05-05 | 1988-08-24 | Zeiss Jena Veb Carl | Verfahren zur definierten ausleuchtung der projektionsflaeche in einem entzerrungsgeraet |
JPH02208646A (ja) * | 1989-02-08 | 1990-08-20 | Fuji Xerox Co Ltd | フイルム画像読取装置の濃度補正方式 |
-
1988
- 1988-12-29 IT IT8806724U patent/IT218047Z2/it active
-
1989
- 1989-12-18 JP JP90501718A patent/JPH03503092A/ja active Pending
- 1989-12-18 EP EP90900854A patent/EP0408697B1/de not_active Expired - Lifetime
- 1989-12-18 US US07/573,180 patent/US5128710A/en not_active Expired - Fee Related
- 1989-12-18 WO PCT/EP1989/001559 patent/WO1990007728A1/de active IP Right Grant
- 1989-12-18 DE DE90900854T patent/DE58906045D1/de not_active Expired - Fee Related
Non-Patent Citations (1)
Title |
---|
See references of WO9007728A1 * |
Also Published As
Publication number | Publication date |
---|---|
US5128710A (en) | 1992-07-07 |
IT218047Z2 (it) | 1992-03-30 |
EP0408697B1 (de) | 1993-10-27 |
DE58906045D1 (de) | 1993-12-02 |
JPH03503092A (ja) | 1991-07-11 |
WO1990007728A1 (de) | 1990-07-12 |
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